Precision Truck Training Technical & Product Training for the Light Truck Specialist

LT●2 LIGHT TRUCK ESSENTIALS General C O U R S E

By James E. Godfrey and Robert J. Godfrey

Second Edition — January, 2015

Truck Marketing Institute Distance Training Courses in Truck Selection & Application Page Introduction

We recognize that some words, model names and designations, for example, mentioned herein are the property of the trademark holder. We use them for identification purposes only. This not an official publication.

No part of this publication may be reproduced by any means without prior authorization of the copyright holder.

First Edition – 2007 Second Edition – 2015

Printed in the U.S.A.

Light Truck Essentials Precision Truck Training TMI

A 15 Introduction Page FOREWORD Congratulations on your commitment, and welcome to Truck Marketing Institute and our LT-2 course. This book will serve as the cornerstone for your studies in this five lesson course; with it you can study when and where you like, an aspect of the flexible training that has made TMI popular for over 50 years. Our Mission: To assist you in developing an understanding of fundamental principles coupled with in-depth truck product knowledge. To teach the fundamentals, we have created a fictional line of trucks and SUVs that go by the name Shadow. The Shadow model line provides a cross section of contemporary truck design and specifications to provide the best instruc- tional benefit. Depending on needs, you are enrolled in one of these specializations: General Course is our non-brand specific version. Ideally suited for anyone working with a variety of makes, or with limited access to factory product information. The Shadow Data Manual included at the back of this binder provides comprehensive specifications for our TMI range of truck models—from minivan and SUV through light- and medium-duty trucks (with gas or diesel engines throughout). MAKE Specialized versions are tailored to those focusing on a specific brand of truck. Students study our Shadow line of trucks to learn the principles. The Product Studies section includes a study guide for your truck make as well as the Shadow models. You will make many references to your product data sources, in your studies, and doing your end-of-lesson tests. Your Mission: Go full throttle at absorbing each lesson; then test your performance with each of the five exams. Strive now, and in a short time you will very likely join the many TMI graduates who sincerely believe that knowledge is the key to greater rewards.

James E. Godfrey Robert J. Godfrey Director Emeritus Director and CEO

TMI Precision Truck Training Light Truck Essentials

A 15 Page Introduction

Contents Introduction 3 Foreword— and we’re here to serve you! 4-6 Contents 7 Objective: Being a Truck Professional 7 Truck Marketing Institute: Mission Statement 8 How to Study Effectively 9 “What if I Get Stumped?” 9 Taking the Tests 10 Grading Policy 10 What is a Good Score? 10 Six Month Enrollment Term 11 Employer Follow-Up 11 What is a Good Study Pace? 11 To Mail or to Fax? 12 Group Study Policy 12 You’re Working for This! 13 Score Card 15 Course Evaluation Survey Lesson: 1 18 Light Truck and SUV Market 18 Why Trucks are Popular 19 SUVs: Then and Now 20 An SUV by the Book 21 Chassis Drive Types 22 Architecture: Engine, Transmission, Drive Axle 26 Engine Nomenclature 29 Truck Weight Ratings 30 Calculating Equipped Curb Weight 31 Accounting for Occupant Weights 31 Allowed Payload and Cargo Load 32 Calculating GVW 32 Basic Truck Dimensions 33 “Just Show Me a Half-Ton Truck” 33 Truck Weight Rating Systems

Light Truck Essentials Precision Truck Training TMI

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Lesson: 2 36 Understanding Load Capacity 36 Frame Types and Designs 37 Truck Strength Starts With Frame Strength 37 Section Modulus 37 Yield Strength 38 RBM: Resisting Bending Moment 38 Bending Moment: What is It? 39 Suspension Systems Defined 39 Front Axles and Suspensions 40 Rear Axles and Suspensions 41 Types of Rear Axles 41 Rear Axle Housings 42 Axle Drive Gears 43 Differential Assembly and Controls 44 Springs and Spring Ratings 46 Shock Absorbers and Stabilizer Bars 46 Tires and Wheels 46 Radial versus Bias-Ply Construction 47 Tire Tread Designs 48 Tire Sizes and Dimensions 49 Tire Load Ratings 49 P-Metric Tires: Truck Application Ratings 50 The Wheel and Tire Relationship 51 Gross Axle Weight Ratings Lesson: 3 54 The Three-Way Test: Obey the Limits 55 Jane and Dick: Sharing the Load 56 Thinking Trucks: Sharing the Load 57 Weight Distribution in Percentages 58 Weight Distribution: Shadow S80 Pickup 60 The Full-Size SUV: Pushing the Limits 61 Weight Distribution Anomalies 62 Weight Distribution: The Big Picture 65 The CGA: Body-Load CG to Rear Axle 66 Dump Trucks: Special Considerations 68 Chassis-Cabs: The Body Connection 72 Equipment add-on Weights

TMI Precision Truck Training Light Truck Essentials

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Lesson: 4 74 The Basics: Work, Torque and Power 75 First Comes Torque, Then Power 78 The Powertrain- From Engine to Axle 79 Transmissions: Performance Stairways 82 Finding Engine Speed at Any Road Speed 83 Harnessing the Horsepower 85 Finding Geared Speed — Choosing Axle Ratios 86 Automatic Transmissions: How They Differ 87 Manual Transmission Anatomy 88 Powertrain: Gearing, Torque, Power, Friction 90 Drive Wheel Power Demands 92 Performance: Putting it Together 95 Cruising on the Level: The Case for Economy 96 What Happened to Friction Power Loss? 96 The Power Balance Lesson: 5 98 4x4s: Another Look 98 4x4 Variations: Part-Time and Full-Time 99 Locking Hubs and Differentials 99 Trailering with Trucks 100 GVW, GTW and GCW 100 Trailer Tongue Weight Distribution 101 Load Distribution: Dead Weight Hitch 102 Weight Distributing Hitches 103 The Five Trailer and Hitch Classes 104 What About Towing Capacity? 104 The Fifth-Wheeler Tow: Pushing the Limits 106 Truck-Trailer Highway Performance 108 The Power Robbers: Altitude and Heat 108 Turbocharged versus Naturally Aspirated 109 Diesel and Gas Engines: More Differences 110 Alternative Fuel Vehicles (AFV): The Basics 111 Hybrid Gas-Electric Powertrains 111 Electrical Systems Basics 113 Cooling Systems (aka Temperature Control) 115 Steering, Brakes and Vehicle Control 119 Working Trucks and Power-Take-Offs 119 Fuel Economics: Think Big Picture 122 What Shall It Be: Gas or Diesel? 124 Vocations for Diesel Power 124 Cross Roads and New Horizons Appendix 125 Tables & Data 132 Glossary Index 137 Product Studies 1 Shadow Data Manual 1

Light Truck Essentials Precision Truck Training TMI

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Introduction

Objective: Being a Truck Professional Being a truck professional may take one of several forms. Your function may be truck sales or leasing, or you may be a purchasing man- ager. For both the seller and buyer sides of that transaction desk, mutual truck professionalism enhances the process and will assure the right truck—or fleet—for the service requirements. Helping to establish your credibility as a truck professional is the objective of our TMI Precision Truck Training Courses. By completing this course, you will find that your confidence has increased because you’ve got a good dose of truck fundamentals filed away for use when you need it. The market for SUV’s, light- and medium-duty trucks is huge and the buyers are many and diverse. Overall, however, they buy trucks because they perceive trucks will do something for them that cars can’t. Selling with precision means that you can recommend the right truck for the right buyer, the first time, and every time! Truck Marketing Institute: Mission Statement Truck Marketing Institute was founded in 1964 to write specialized training courses for those who sell and operate trucks. Our mission is to deliver up-to-date training programs that will substantially increase the sales engineering skills of not only truck sales representatives, but also those personnel in related fields of fleet

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A 15 Page Introduction

Courses that have educational value. Honest advertising practices. A fair tuition refund policy. A history of student success and satisfaction. Financial stability to assure a quality educational service. How to Study Effectively Here are a few things we have learned from students that will help you to study most effectively. 1. Schedule a study period so you can read a complete lesson. Then “sleep on it.” Seriously, science tells us it works; even as we sleep that marvelous human brain keeps on clicking. Next day, read again; the extra clarity may surprise you. 2. Pick a time, place, and environment for studying that suits your style. For some, it could be a quiet room. Others may want back- ground music. 3. Get all your study materials together before you begin. You’ll need this textbook, your product data, scratch paper and a calculator. 4. As you study, stay involved with the text. Make notes in the margins, underline terms, and key phrases. 5. Use a three step method for studying: A. Read the lesson objectives and scan the entire lesson for content; B. Read the lesson completely for understanding; then C. Second day plan: reread it for fuller understanding. 6. After completing the lesson, follow through point by point, on your product studies agenda. 7. Complete the open book test for the lesson and send to TMI for grading. 8. Soon as convenient, move on to the next lesson! When you use the three step study method, your first scanning will pick up paragraph headings, illustrations, and subject highlights. Next, in reading for understanding, go as quickly as you can but with the purpose of trying to understand what is being written. In the third reading, you can hit the points that gave you some trouble. If you put a question mark next to some topic during your second reading, be sure to go back and figure it out.

Light Truck Essentials Precision Truck Training TMI

A 15 Introduction Page “What if I Get Stumped” There will be times when you just don’t understand something. You may find yourself questioning something that doesn’t look right. If that happens, give us a call to see whether we can help. Our normal hours are 8:00 am until 4:30 pm each business day, Pacific time. We normally close on U.S. Federal holidays. If your instructor is not available, please leave a message and we’ll get back to you promptly. We’ll try to clear up your confusion and point you in the right direction. When it comes to test questions, however, don’t count on us giving you the answers! Rather, we will explain the method to reach the answer. But, if we sense a lack of lesson reading, our response is gentle encouragement to read, then call, if need be. And if you do call, just remember that we’re in California, so there may be a time difference. If you want to pay a visit and see what the Pacific Ocean looks like, come on out! We are located 85 miles up the coast from Los Angeles, on U.S. Highway 101 between Ventura and Santa Barbara.

TMI Headquarters 1090 Eugenia Place Carpinteria, CA Ph. 1-805-684-4558 Fax 1-805-684-2868 Taking the Tests You’re not finished with a lesson until you have taken the test prepared for that lesson. Each test is designed to review material covered in the lessons as well as referenced material in your Shadow Data Manual, and for those of you in a make-specific course, your product information. A test for each lesson is placed in the pocket of this textbook binder.

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We are a school, and a test is a test! But that does not mean that we expect you to remember all facts and figures. You are expected to keep your sources open to find the answers. Study before you take the test. Sounds all too basic, but we’ve experienced the rare student who tackles the test, then the lesson. Not a good system; that reverse technique really hurts the chance of a passing grade. Grading Policy Our requirements for completion are simple. First, you must success- fully complete all five tests. Second, you have to score at least 75% on each test. Third, your overall average must be 80% or better. If you score below 75% on a test, it will be returned to you so you may rework it. If the instructor feels you were probably just too rushed, you will be instructed to take a bit more time and reread the lesson. You may also be given some suggestions about specific references to review before completing the test. You can score a maximum of 90% on a reworked test. If you fail it repeatedly, the instructor will ask you to try the test one last time on a pass/fail basis, with a passing score being 75% and failing being no score. What is a Good Score? Since the tests are open book and the material is relatively easy, you should expect fairly high scores. However, point values on individual questions on LT-2 tests are valued at two or three points; so you can also lose them in a hurry! If you can score 95% or better, we would call that an “A” score. Down to 90% would be a “B” while a “C” effort could hit 85%. Be- low that, you really are in the “danger zone” and should think about working just a little harder! Six Month Enrollment Term The beauty of our TMI system is flexibility, allowing you to study at your own pace — but there need to be time limits. Your five-lesson course has a six-month enrollment term. But, we recognize the pres-

Light Truck Essentials Precision Truck Training TMI

A 15 Introduction Page 11 sures of business. When push comes to shove, we have empathy, let us know; we do offer extensions. Employer Follow-Up With rare exceptions, enrollments are paid for by employers, who consider these materials to be company property. If you leave, they have the right to transfer the course to another employee for a fee that consists of a registration fee plus charges for completed tests. Because this is employer-paid training, most of them want to be notified when you don’t send in a test within 30 days or so. Normally, we’ll send you a note at the 30 day point. After that, we are obliged to notify your employer. As your course expiration date approaches, we do forward a notice informing the employer of the available options (extension, transfer, etc.). What is a Good Study Pace? For this course, a good pace would be a goal of submitting one test each week. That way, you keep sharp and don’t forget material from the last lesson. There are a few students who will sit down with this course and knock it out in a week or two. It’s really a matter of your commitment to time management balanced with business pressures. To Mail or to Fax? When you’ve finished a test, you can either put it in the postpaid en- velope and mail it, or slip it into the fax machine for quicker service. (Keep the originals if you fax and keep copies if you mail). We try to grade all tests the same day they are received, but if a fax comes in after the instructor leaves, it probably will hold over to the next day. If you fax a test, be sure to send both sides! (Don’t laugh, it’s an easy oversight). Make sure to include your fax number and/or email address so we can advise you of your test score. We will grade your paper and return it to you via mail (not fax).

TMI Precision Truck Training Light Truck Essentials

A 15 LESSON 1 Lesson Objectives This is the start of your journey into a deeper understanding of trucks and SUVs. As an added bonus, this same knowledge will flow over into the appreciation of passenger cars. The broad objective of this first lesson is to pour the footings and shape a foundation for each topic that will follow on this pathway to truck professionalism. That calls for a diversity of subjects over these coming pages — a series of introductions into the world of light trucks and SUVs. Here is the agenda that takes you forward:  Recognizing the large size of the SUV and truck markets  Buyer’s perceived values of trucks and SUVs  Sorting out the players: categories of trucks and SUVs  Vehicle architectures: the platforms, the chassis types  Defining the driveline types: 4x2, 4x4, all-wheel drive  Power teams as related to rear-drive or front-drive  Engine types and design basics; specifications insights  Truck ratings: understanding GVWRs and GVWs  Working the ratings: GVWR, curb weight, payload capacity  Truck dimensions: know the language and abbreviations  Lesson wrap-up: the whole story on truck “tonnage” ratings. As you move through these diverse topics, if you are taking a make- specific course, think in the context of your line of trucks and SUVs. Your time for these specifics will also come through the product

TMI Precision Truck Training Light Truck Essentials

A 15 Page 32 Lesson 1 Calculating GVW— Gross Vehicle Weight GVW was defined a few pages back; now let’s revisit with a set of numbers. We’ll use the same crew-cab weights. What you see here is a simple shifting of the elements of the cargo weight equation: Equipped Curb Weight + Occupants + Cargo = GVW Equipped Curb Weight 5015 lbs Plus: Occupants (150 x 4) 600 Plus: Cargo Weight 785 Equals: Gross Vehicle Weight 6400 lbs No surprise here. The GVW comes out identical with the GVWR because we used the Allowed Cargo Weight figure as the actual load. Once again, the equipped curb weight picks up any and all weights (add-ons) of options, as well any locally installed equipment. Basic Truck Dimensions Commercial truck buyers can be expected to have a special interest in cab, chassis and body dimensions. Certain key dimensions prevail from light pickups to big rigs; we illustrate them with the generally

accepted letter abbreviations. ➛ Figure 1–11

➛ BBC

➛ IL ➛ ➛

OH ➛

➛ CA ➛

➛ ➛ ➛ BA ➛ WB ➛ ➛ OL WB: Wheelbase, front axle to rear axle BBC: Bumper to back of cab OL: Overall length, bumper to bumper IL: Inside length of body BA: Bumper to front axle OH: Overall height to roof CA: Cab-axle, back of cab to rear axle another key dimension is tread width (TW) or track width. For this, we show a bare chassis in rear view. As you see, width is measured

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to the centerlines of the single tires, or the center of the dual wheels. If the overall width with dual wheels exceeds 80 inches, you’ll see clearance lights on the cab roof — all part of lighting codes for bigger trucks. Figure 1-12

TW TW “Just Show Me a Half-Ton Truck” The general public often speak in terms of half-ton or three-quarter ton pickups. As you know, there are a number of variables when it comes to cargo capacity. Ton ratings are simply an informal reference to the general size category of a pickup. You might say, the pecking order. Where a line of pickups comes in three weight ratings, it boils down to half-, three-quarter and one-ton. But, a formal system of weight classes and GVWR groups goes all the way up to the big rigs—long haul 18-wheelers and the like. Sales and registrations of trucks are counted by these formal weight Classes 1 through 8. TRUCK WEIGHT RATING SYSTEMS GVWR Gross Vehicle Weight nominal Weight Class Ratings (pounds) Ton Ratings Group 1 1 6,000 or Less /2 -ton 3 2 6,001 to 7,500 /4 -ton Light Duty 7,501 to 10,000 1-ton 1 3 10,001 to 14,000 1 /2 -ton 4 14,001 to 16,000 2-ton 1 5 16,001 to 19,500 2 /2 -ton Medium Duty 6 19,501 to 26,000 *N/A 7 26,001 to 33,000 *N/A 8 Over 33,000 pounds *N/A Heavy Duty *N/A: Not applicable; ton ratings are irrelevant above 19,500 pounds

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Those informal ton ratings are becoming less likely to match the actual GVWR or Class. The lightest “half-ton” pickup in the line-up may now register as a Class 2 with a 6400 pound GVWR. Three-quarter and one-ton models have also jumped in weight classes. Those heavier GVWRs are due in part to product and market competition. And the heavier ratings are also a byproduct of the stronger chassis and suspensions required for larger cabs and popular passenger car- like luxuries. This concludes the textbook portion of this lesson. Read again or review as you feel the need. Next read the Product Studies section(s) for this lesson located behind the tab at the back of the book. After that, complete your Achievement Test. Mail or fax it (1-805-684-2868) for review and prompt grading by your instructor.

Light Truck Essentials Precision Truck Training TMI

A 15 LESSON 2 Lesson Objectives Your first lesson dealt with weight factors —curb weight, load weight and gross weight, along with the truck rating, its GVWR. That creates the situation to deal with the whole truck as a load carrying machine. In that sense, we’re talking about all the components that factor into load capacity: frame, suspensions, wheels and tires. For the typical buyer of a work truck, specifications can be vital to the purchase de- cision. And believe it, the frame and all that mounts on it comprise a laundry list of specs (as we’ll say for specifications). So the overall objective here is to shape a comfortable familiarity with these components, along with interpretations of their published specifications. All this will enable you to:  Know the structure of truck frames: types and designs, frame steels and measures of frame strength  Understand suspensions as a system of components: axle, springs, shock absorbers, alignment linkages, stabilizer bars, wheels and tires  Be aware of the various types of axles and independent suspensions  Distinguish between semi- and full-floating axles  Be familiar with the different kinds of springs, how they are rated, and what the ratings mean  Be aware of the types of tires, with an understanding of tire sizes and load ratings as designated for truck applications  Be cognizant of the size relationship of tire and wheel widths  Understand Gross Axle Weight Ratings (GAWRs) and how to calculate them With your understanding of these truck fundamentals, you will be at ease and self-confident in most any discussion about light truck load components.

TMI Precision Truck Training Light Truck Essentials

A 15 Page 36 Lesson 2 Understanding Load Capacity So far the approach to truck load capacity has been limited to end results: GVWR is this much, curb weight is that much, and payload capacity is the difference between the two. With that knowledge as a base, you are well versed to examine the load sharing components of light trucks and SUVs — and it all begins with the truck frame. Frame Types and Designs The frame is the backbone of the modern truck. A truck frame takes on the appearance of a ladder when viewed from above, so we call them ladder frames. Two side members (the side rails) are joined by a series of cross members, giving that ladder look. While medium- and heavy-duty trucks have parallel rails close to 34 inches across, frames for pickups typically are wider under the cab, then narrow inward behind the cab (but wider than 34 inches). Also, light-duty frames usually have a kick-up above the rear axle; that lowers the step-in height onto the cab or body. Briefly now, let’s deal with the “non-frame,” known as unibody or unitized body-frame construction. That design comes into play for passenger car based vehicles — minivans and crossover SUVs. Over six decades ago, Nash pioneered the integrated body and frame design; curb weight was trimmed some 500 pounds while fuel mileage was enhanced. But, traditional body-on-frame technology predominated until the sweeping downsizing of cars during the 1980s. Unitized design coupled with smaller bodies and front drive whacked off hundreds of pounds of curb weight. Today, very few cars have a separate frame, so the body on frame is almost exclusive to trucks and truck-based SUVs.

Ladder Frame 2–1

Light Truck Essentials Precision Truck Training TMI

A 15 LESSON 3 Lesson Objectives Big and bold, here you see the standard symbol for center of gravity — CG for short. It will make itself well known in this lesson. You may be familiar with the CG symbol as it is used on those death defying, bionic crash test dummies. In the context of this lesson, the CGs are the focal points of our discussions about weight distribution. Which is? Simply put, how much weight goes front and rear, speaking of axles. This will take you on a journey from a basic parable of Jane and Dick upwards, from pickups and SUVs into a couple of bigger trucks. Perhaps bigger than you work with. But have faith; they serve to solidify your understanding of weight distribution. along the way, you determine allowable cargo weight, leading up to that Three-Way Test of axle loads versus ratings. Those are the general goals of this lesson. More specifically, here are the topic headings along with a few comments.  The Three-Way Test: Obey the Limits. This is your introduction to weight distribution.  Jane and Dick: Sharing the Load. A look at weight distribution, up close and personal.  Thinking Trucks: Sharing the Load. From Jane and Dick we 1 transition to a /2-ton pickup.  Weight Distribution in Percentages. Do percentages come easily or not? This is how it’s done.  Weight Distribution: Shadow S80 pickup. Every step in the process, through to the Three-Way Test.

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 The Full-Size SUV: Pushing the Limits. Excesses, and how to avoid them.  Weight Distribution Anomalies. Loads outside the wheelbase and the seesaw effect.  Weight Distribution: The Big Picture. Raising your sights with a look at bigger trucks.  Urban Delivery Van: They’re everywhere. The cab without a hood. Examining the advantages.  The CGA: Body-Load CG to Axle. Understanding this key dimension for any body on a chassis-cab.  Dump Trucks: Special Considerations. Why dumps are different from fixed bodies.  Chassis-Cabs: The Body Connection. Procedures plus conventional wisdom about the critical match of truck chassis and body. That is the menu for Lesson 3, so take it from here. The Three-Way Test: Obey the Limits It’s time to build on the foundations laid in Lesson 2, aimed at the fact that each vehicle has three weight ratings: GVWR along with the front and rear GAWRs. Vehicle is the right word here, because those same three ratings apply to cars as well as SUVs and trucks. You know how GAWRs are derived, and it’s not a good idea to overload a suspension system. Further, you know what goes into the mix that ends up as Gross Vehicle Weight: curb weight plus people plus cargo weight. So is the GVW less than the GVWR? And are the axle loads less than the GAWRs? So goes the Three-Way Test: ❶ Front GAWR, ❷ Rear GAWR and ❸ GVWR. The knowledgeable truck specialist (as you strive to be) can give assurance that the proposed SUV or truck will operate within these bounds. Short of driving over a load scale, one axle at a time, how can you determine axle loads? In the truck business this is known as Weight Distribution Analysis. Think about it: each and every item on a truck, the occupants and where they sit, and the location of the cargo — they all affect the loads at the axles. That’s where we are heading in the pages that come. It starts with the basic principles, featuring Jane and Dick. But first, this definition of weight distribution:

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A 15 Lesson 4 Page 73

LESSON 4 Lesson Objectives Lesson 4 is all about vehicle performance. That takes you from engine to drive axle, and all that comes between. In the pages ahead, explore the relationship of torque and power. Like the chicken and the egg, you can’t have one without the other. But in this case there will be no mystery over which comes first. Fine tuning of vehicle performance relies on choices of axle ratios and transmissions, be they manual or automatic. And with small trucks, as with big trucks, performance ability is predictable. Truck power demands can be calculated, and then, in total, compared with engine power output. This lesson shows how it’s done. So climb aboard and become well versed on the following:  Understanding “Work” as it relates to torque and power. That leads to the connections between torque and power.  Getting acquainted with the curves: torque and power, along with this defining number: 5252.  Comparing gasoline and diesel engines; their differing torque, power and operating speeds.  Understanding the powertrain, from engine and transmission to rear axle.  Axle gearing ratios: how they affect vehicle performance and economy — fuel mileage.  Harnessing engine power output by transmission gearing. Comparing manual and automatic transmissions.  Working with the numbers: Vehicle road speeds as related to engine rpm, axle ratio, tire size and transmission ratios. All this toward mak- ing the right decisions for the best powertrain combination: “the right truck for the job.”

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 Power demands of the energy eaters: tires as they roll, air/wind and grade climbing demands — as well as frictional loss from engine to drive axle.  Identify and tally up those power demands to the point of predicting gradeability, namely how steep a hill at the given vehicle speed. And that’s the agenda for Lesson 4, all toward understanding vehicle performance as influenced by component choices. Another block of knowledge in the credentials of the well-versed truck professional. The Basics: Work, Torque and Power Rarely an automotive advertisement fails to mention horsepower, or at times, torque. Question is, what’s behind it all? Folks talk about horsepower like they talk about the weather. Now, like a certified me- teorologist knows weather, you can be well versed in all that makes up those key words—torque and horsepower. But before torque, comes work, so let’s deal with it. Work, in a personal sense, comes to mind as 9 to 5 Monday to Friday, or some other shift that pays the bills. Here we are talking of work in the high school science mode. In science, work is done when a force moves an object. It is measurable too, in terms of feet of distance and pounds of applied force. As abbreviated, work is ft-lbs, coming from the multiplication of force times distance of movement: Work (ft-lbs) = Distance (ft) x Force (lbs) Suppose a crane lifts a 200-lb block a vertical distance of 9-ft; the resultant work would be: Work (ft-lbs) = 9-ft x 200 lbs = 1800 ft-lbs For the vertical lift, the 200-lb force is needed to overcome the pull of gravity (on a 200-lb mass, by science terminology). Force and motion can occur in any direction: vertical, or on an angle (as in climbing a hill) or in rotation (pedaling a bicycle). And like the bike reference, a car or truck engine performs work in a circle, which leads us to torque. When work moves in a defined circle the mea- surement becomes torque. Or in a defined arc for that matter, such as the muscle force required on a wrench to loosen or tighten a nut.

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Transmission Gear Ratio Steps -4 Shown to scale here, like a bar chart, are the ratio steps from 1st to 6th gear.

Gear 1st 2nd 3rd 4th 5th 6th Ratio 5.79 3.31 2.10 1.31 1.00 0.76

60 mph Road Speeds -5

Again to scale, here are the road speeds 46 for the truck when shifted at 2200 rpm for each gear. 35

14 8 S peed i n M l es per ho u r Gear 1st 2nd 3rd 4th 5th 6th An engine speed of 2200 rpm was chosen, so it may be either a diesel or gasoline engine. What’s more, 2200 rpm at 60 mph is an easy cruising speed for either engine. Now it’s time to have a look at how these road speeds were determined. Here are the factors that set the relationship between engine speed (rpm) and vehicle road speed (mph):  Engine speed in rpm  Gearing ratios of transmission and axle  Tire size, for tire revolutions per mile  Number constant 60 (minutes per hour) A logical benchmark for those who choose truck axle ratios is this: road speed at peak engine power. The alternative, as it applies to diesel

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LESSON 5 Lesson Objectives This final lesson wraps up our mission that includes coverage of technical issues that will assist you in developing a sense of confidence and knowledge, over a wide range of truck topics. Touched lightly in Lesson 1, there’s more to say about 4x4s and AWDs. And trailer towing comes with the territory of light-duty trucks, and SUVs as well. More about engines, too, especially about diesels and turbocharging. Then there are the alternatives to gasoline as a spark-ignited fuel. It’s well to understand the specifications of the several support systems: steering, brakes, vehicle control—and how they might integrate. As work trucks go, which powertrains are PTO compatible? Like the weather, everybody talks gas mileage, but there’s more to it than MPGs, so explore the fundamentals of fuel economics with us —no Einstein stuff, just common sense observations. And with that to build on, work with fuel cost and MPGs in comparisons of gasoline or diesel power economics for your truck applications. Here is a summary of topics covered in Lesson 5:  4x4 variations; locking hubs and differentials  Trailering: hitch classes, fifth-wheelers  GCWRs: pushing the limits for loads, performance  Exposing the power robbers — heat and altitude  Turbocharged or naturally aspirated (what’s that?)  The fuel choices: diesel, gasoline or alternatives  Hybrid gas-electric powertrain technology  Electrical system basics: volts, amperes, CCAs as they relate to batteries, alternator and cold starts  Cooling system components, their specifications and keeping a healthy engine temperature  Steering systems, brake types, braking and vehicle stability control systems

TMI Precision Truck Training Light Trucks Essentials

A 15 Page 98 Lesson 5

 Power take-offs for the serious working trucks  That matter of fuel economics: world oil pricing, supply and demand, per-gallon costs and MPGs as they influence engine choices — gasoline or diesel. Here we will pull together these diverse topics, some of which we cover for the first time, others that are dealt with in more detail than in earlier lessons. 4x4s: Another Look Lesson 1 gave an introduction to 4x4s and AWDs, as part of an over- view of truck chassis types. At this point the story gets deeper. We start with more detail on the transfer case, the gearbox that divides engine torque between the front and rear axles. Looking back a few decades, 4x4 trucks were not all that commonplace; the market was utility and construction trucks, off-road fans, and of course, the snowbelt regions of North America. That kind of slogging calls for maximum torque at the drive wheels. The 2-speed transfer case, in low range, gives that torque boost to the drive axles. Transfer case low-range ratio typically is on or about 2.70 to 1, so 2.70 becomes the torque multiplier. But, bear in mind, where a transfer case splits torque equally front and rear, that extra torque multiplier is one-half of 2.70, or 1.35. That means a 35% boost of engine torque to each axle. That’s how the “true 4x4s” with 2-speed transfer case get the extra mobility when the going gets tough. 4x4 Variations: Part-Time and Full-Time Commonly found in light trucks is the 4x4 system known as “Part- Time,” and here is why: The drive from transfer case to front and rear axles is a solid hookup; there is no device to compensate for different wheel speeds, as when turning a corner. Front and rear tires must be of the same size, and the axle ratio is identical, front and rear. Even so, turn a corner and one wheel fights another. And that leads to the part- time stipulation: 4x4 engagement is advised only for off-road or with a specific loss of highway traction—be it wet, snow or ice covered. “Full-Time” 4x4 systems differ in this respect: Integrated with the transfer case is a differential. The differential gears function like those in a rear axle, compensating for wheel speed variations between the

Light Truck Essentials Precision Truck Training TMI

A 15 Page 100 Lesson 5 GVW, GTW and GCW As a review, you know that the loaded weight of a truck is known as its GVW, or Gross Vehicle Weight, and that GVW must not exceed the GVWR (Gross Vehicle Weight Rating). Similarly, we call the weight of a loaded trailer the GTW, for Gross Trailer Weight. Adding together the weights of truck and trailer gives you the Gross Combination Weight, abbreviated as GCW. Maximum load ratings apply to GCWs too, known at the GCWR, for Gross Combination Weight Rating. (Some favor the word Combined as applied to GCW and GCWR.) When it comes to trailering and following the recommendations for powertrains, pay attention also to the load limitations; these may be shown either as a maximum GTW, a specified GCWR, or both. Understand here that the GTW alone tells only half the story, given that there can be huge differences in loaded GVW of the truck itself. Examples: is it a regular cab or crew cab pickup; driver alone or four occupants? Such can be the variations and their impacts on the GCW for the truck-trailer combination. So let’s have specifics: Recall from Lesson 3, pushing the limits of an SUV, the Shadow S100HD-SUV. Here it is again, not as yet hitched with the family travel trailer. Follow the gross axle weights for the SUV and its GVW prior to hook-up. And the trailer GTW, the sum of the axle load plus the tongue weight, as it will ride on the hitch. S100HD-SUV & Trailer 5-1

2803 3827 340 3060 GVW: 6630 GTW: 3400 GCW: 10,030 Trailer Tongue Weight Distribution That trailer behind the SUV is “road ready,” meaning loaded with gear and supplies. Of its 3400 lbs GTW, 10% or 340 lbs goes to the tongue, which will become the load at the trailer hitch. Actually, a

Light Truck Essentials Precision Truck Training TMI

A 15 Page 124 Lesson 5 Vocations for Diesel Power Here are some of the many business types that might profit from a fuel economics analysis. Air Freight Forwarders Vending Service Bakeries and Caterers Dry Cleaning Service Linen Supply Firm Linen /Diaper Service TV / Radio Mobile Unit Carpet Cleaners /Installers Department Store Delivery Courier / Messenger Service Newspaper Delivery Moving & Storage Firms Office Supply Firm Musical Instrument Dealer Janitorial Service Magazine & Book Distributor Ambulance Service Police/ Fire/ Rescue Squad Food / Beverage Distributor Mobile Sales Office Airport Shuttle Van Employee Carpool Van Construction Company Surveying Company Plumbing Contractors Farm and Ranch Operations

Cross Roads and New Horizons Reflecting upon your bonding with trucks, does this mark the beginning of the end? Or rather, the end of the beginning? At this point you should feel a deep self confidence and high comfort level with trucks. That spells professionalism, and it promises to serve you well on a truck career path. Along the way, this will be your primary asset: A Good Reputation. Over time, each proper truck application will add another tribute to your truck know-how. Results will pyramid for you: goodwill and loyalty; growth through referrals. These are a few of the rewards of success.

Show us your best on your final test! And as a parting suggestion, do as thousands of TMI graduates have done over the years: Keep this textbook as your continuing truck handbook. It can be your reference and solution when special problems or conditions arise. And as a TMI alumnus, feel free to call us if you get really stumped.

Light Truck Essentials Precision Truck Training TMI

A 15 Appendix Page 125

Appendix Tables & Data

Appendix Page 126 Weights and Measures/Metric Equivalents 127 Tires: Load and Inflation Data 128 Table 1: Tire-Axle Combinations & Engine Speeds 129 Table 2: Rolling Resistance Net HP Required 129 Table 3: Frontal Areas: Light Trucks & Bodies 130 Table 4: Air Resistance Net HP Required 130 Table 5: Grade Net HP Required 131 Table 6: Road Surface and Effects on Performance 132-136 Glossary: Common Truck Terms

TMI Precision Truck Training Light Trucks Essentials

A 15 Page 132 Appendix

GLOSSARY OF COMMON TRUCK TERMS

AIR INJECTOR REACTOR Reduces unburned hydrocarbons and carbon monoxide to allowed levels by pressure injection of fresh air at exhaust ports; oxygen ignites unburned hydrocarbons. ALTERNATOR Alternating Current electrical generator; a diode rectifier, integrally-mounted or separate, changes output to direct current for vehicle electrical system. AMMETER An instrument that indicates current flow in amperes, either discharging (-) of the battery, or charging (+) of the battery by the generator. AUXILIARY SPRINGS Secondary spring for rear axle; takes effect upon heavy loading. Also known as helper springs. AXLE, FULL FLOATING See Lesson 2. AXLE, HYPOID See Lesson 2. AXLE, SEMI-FLOATING See Lesson 2. AXLE RATIO See Gear Ratio. Also see Lesson 4. BBC Distance from front bumper to back of cab. Biodiesel Fuel derived from vegetable oils or animal fats. BORE The diameter of an engine cylinder. CAB-OVER (CAMPER) Extension of camper body over the truck cab. “Cab-over” trailer has a similar bunk projection over the tongue assembly. CAB-OVER (TRUCK) Short BBC design; cab is over the engine. CA DIMENSION Distance from back of cab to centerline of rear axle. CARGO WEIGHT Combined weight of all loads, gear and supplies on a vehicle-car, truck or trailer. CATALYTIC CONVERTER Positioned in exhaust system between exhaust manifold and muffler, catalytic converter changes carbon monoxide and unburned hydrocarbons into carbon dioxide and water. CE DIMENSION Frame length, from back of cab to end of frame. CG (Center of Gravity) The weight center or balance point, of an object-truck, body, a passenger, cargo or item of equipment. The symbol for CG is: CLOSE-RATIO (Transmission) In terms of their numerical ratios, gear ratios are closely stepped. These ratios are typical of a close-ratio 5-speed transmission: First-4.02; Second-2.41; Third-1.41; Fourth- Direct; Fifth-0.76; Reverse-4.42. COE See Cab-over (Truck)

Light Trucks Essentials Precision Truck Training TMI

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Index

A B Acceleration Balance shaft 23 and axle ratio 79 Batteries Adverse surface resistance 92, 131 and gas-electric hybrid 111–112 Aftercooler / Intercooler 109 in series 112 parallel 112 Air bags (as springs) 44 Bending Moment 38–39 Air resistance 91, 92, 94, 96, 130 table 130 Bias ply tires 47 and rolling resistance 91 All-season tire tread 47 Biodiesel 120 All-wheel drive (AWD, 4x4) 22 SUV definition 21 Blazer, Chevrolet SUV 20 Allison, automatic transmission 86 Body-on-frame 26, 36 PTO 119 Bore 132 Allowed payload rating 31 Bore and stroke 28 Alternative fuel vehicles (AFV) Boxer / horizontally-opposed engines bi-fuel vehicles 110 23–24 dedicated vehicles 111 Box rail frame 37 flexible fuel vehicles (FFVs) 110 Brake boosters 117 Alternator 112, 132 Brake fade 117 Ambient temperature 108 Brake systems and SAE net ratings 75 antilock (ABS) 118 Ampere 112 disc 117–118 Antilock brake (ABS) 118 drum 117 Antispin / antislip differential 99, 118 dual hydraulic 116 Architecture (driveline layout) 22–23 Bronco, early Ford SUV 20 Aspect ratio 48 Buick early OHV engine 27 Audi longitudinal fwd 25 longitudinal fwd 25 Bumper to back of cab (BBC) 32, 132 Automatic transmissions 86–87 Auxiliary springs 45, 132 Axle ratings full-floating 42 semi-floating 42

TMI Precision Truck Training Light Truck Essentials

A 15 Page 138 Index C Cylinder block 23, 24, 27 Cylinder head 27 Cab-over 132 Cab to axle (CA) 32, 63, 66, 68 D Cab type Deflection rate, springs 44–45 conventional 66 conventional crew 69 Demand horsepower 90–93 low cab forward (LCF) 63, 69 Diesel engine Cadillac compression ignition 26 longitudinal fwd 25 compression ratio 29 performance, horsepower 77–78 Camshaft 27 performance, torque 76 Carburetion 109, 133 turbocharging 108 Cargo weight 31, 132 vs. gas 110, 122 vs gas 122–123 Center of gravity (CG) 53, 132 from front axle (CGf) 56 Differential 43, 133 from rear axle (CGA), (CGr) 56–57, in driveline (AWD, 4X4) 22, 98–99 60–61, 65, 69, 70 Dimensions, abbreviated 32 Channel frame 37 and body compatibility 68 Chassis-cab 63, 66, 68–69 Disc brakes 117–118 Chevrolet Displacement, engine size 28 Corvair, boxer engine 23–24 Dodge Ram SUV 20 early OHV engine 27, 27–28 Double I-Beam IFS 40 Clutch, lockup 87 Double Wishbone IFS 40 Clutch disc 86 Driveline friction loss 89–90, 96 Coil spring 44 Driving front axle 40 Cold Cranking Amperes (CCAs) 112 all-wheel drive (AWD) 22 Component ratings (suspension) 51–52 four-wheel drive (4x4) 22 front-wheel drive (fwd) 21–22 Compression-ignition (diesel) engines 26 Drum brake 117 Compression ratio 29 diesel engines 109 Dual wheels 33 Computers, electronic control Dump trucks 66–67 and traction 43 Dynamometer testing 75 anti-slip, traction 118 braking 118 E fuel injection 77, 84 Electrical Systems vehicle stability 118 ac/dc currents 112 Cooling Systems 113–114 alternators 112 Crankshaft 27 batteries 112 generator (aka: alternator) 112 Crossover (SUVs) 22 starter (cranking) motor 111 car-based unibody 25 system voltage 112–113 dead axle 41 terms 112 Curb weight 30, 133 equipped, as calculated 30–31

Light Truck Essentials Precision Truck Training TMI

A 15 Index Page 139

Electronic / computer controls 118 Ford brake systems 118 Bronco SUV 20 differential assembly overide 43 flat head engine 27 engine performance 77 Four-Stroke-Cycle engine 26 vehicle stability control 118 Four-wheel drive (4wd, 4x4) 22, 98–99 Electronic stability control 118 Frame strength 37–38 Electronic traction control 118 resisting bending moment (RBM) 38 Engine block heater 111 section modulus 37 Engine displacement 28 yield strength 37 Engine speed (RPM) Frame system and axle ratio 79 body-on-chassis 26 and horsepower 77–78 unitized or unibody 25 shift pattern chart 83–84 Friction loss, driveline 90 tire-axle ratio table 128 allowance for 96 transmission gears 83–84 extent of loss 89–90 Engine types and components 23–28 Front-wheel drive (fwd) 21, 22, 24–25 balance 23 Frontal area cubic displacement 28 and air resistance 91–92 cylinder layouts 23 hp required 130 ignition methods 26 square feet 129 valve functions 26–27 Front axles and suspensions 39–40 Engine variations 23–28 balance 23 Fuel economics 119–121 cylinder layout 23 Fuel economy major components 23, 26–28 and axle ratio 79 valve drivetrain 27 and intercooling 109 Equipment add-on weights 72 and turbocharging 108 diesel vs gasoline 110, 122–123 Equipped Curb Weight 30 Fuel injection Exhaust emissions and diesel engine ignition 26 ultra-low-sulfur fuel 121 replacement for carburetor 109 F Full-floating axles 42 Fan, engine G electric 113 gross power 134 Gas engines 22–29 specifications 114 Geared speed thermostatic control 113 and shift pattern chart 84–85 torque loss 114 calculation method 85 torque SAE Net 75 Transmission ratio 85 viscous 113 Gear ratios Fifth-wheel trailer hitches 104–106 axle 78–87, 85 Final drive ratio 89 overall ratio 88 overall reduction 88 Flywheel 86 transfer case 98 transmission 79–80, 88

TMI Precision Truck Training Light Truck Essentials

A 15 Page 140 Index

Generator 111, 112 See also Alternator power reserve and gradeability 92–95, 107 GMC rolling resistance horsepower required 129 Jimmy SUV 20 SAE net 75 the balance of power 96 Governed speed 81 torque output 76–77 applied to engine speed 84–85 applied to vehicle speed 84–85 Hybrid Gas-Electric 111 Gradeability 133 Hypoid axle gearing 42–43 calculation examples 94–95, 107 diameter and torque rating 43 table, power required 130 pinion and ring gear set 42 Grade Resistance power demand explained 92 I table, power required 130 I-Beam axle 39–40 Gross Axle Weight (GAW) Independent front suspension (IFS) 40 calculation examples 61, 62, 64, 67, 102 Independent rear suspension (IRS) 40– Gross Axle Weight Rating (GAWR) 39, 41 51–52 Inflation (economic) Gross Combination Weight (GCW) 100, oil pricing 121 134 Inflation pressure calculation example 101–103, 105 tire ratings 49–50, 52, 127 Gross Combination Weight Rating Inline engine layout 23 (GCWR) 100, 104, 134 Intercooler / aftercooler 109 Gross Trailer Weight (GTW) 100, 104, 134 distribution of fifth-wheel load 104–105 K distribution of tongue load 100–101 Kilowatt (kW) Gross Vehicle Weight (GVW) 30, 33, 134 horsepower equivalent 126 and Three-Way Test 54, 59, 101–102 Kompressor (supercharger) 109 calculation examples 32, 61, 62, 64, 67, 70–71, 101–102 L Gross Vehicle Weight Rating (GVWR) 30, 31, 33–34, 100, 134 L-head (side valve, flat head) engines 27 Ground rating (springs) 45 Ladder frames 36 Launch performance (startability) H and axle ratio 79 overall transmission reduction 88–89 Heap-loading 68 Leaf springs 44 Highway commercial tread 47 Lift-gate 72 Horizontally-opposed engines 23–24 Limited-slip differential 43, 133 Horsepower 75–76, 129, 130, 134 antispin / antislip 99, 118 air resistance horsepower required 130 diesel and gas engines 77–78 Load (weight) distribution 100–101, 134, effects of heat and altitude 108 136 engine speed 76–77 and trailer hitches 100–101 grade resistance horsepower required 130 cargo weight 54, 56–59, 61–62, 64, 67, performance curves 75–78 70 occupant 54, 56, 58–59, 60–61, 67

Light Truck Essentials Precision Truck Training TMI

A 15 Index Page 141

Load capacity Overdrive transmission 79–80, 85 axles 40–41 Overhead cam engines frame 36–39 double overhead (DOHC) 28 springs 44–45 single overhead (OHC) 28 tires 49–51, 52 Overhead valve engines (OHV) 27–28 Load limits pushrods 28 reserve capacity 59, 61, 64, 67, 68, 70, rocker arm 28 71 the three-way test 54, 59, 101–102 P Load rating P-metric tires 48–50 of cargo weight 54, 64, 67, 71 of trailer weight 103–105 Pad rating (springs) 44–45 Long wheelbase Payload, defined 31, 135 frame strength 39 Payload rating 31 Low-cab-forward (LCF) 63 Performance (of vehicles) adverse road effects 92, 94–95 M altitude and heat effects 108 Manual transmission 87–88 axle ratio effects 79 calculation examples 93–95, 106–108 Mercedes-Benz 109 friction loss 89–90, 96 Metric equivalents 126 transmission effects 84–85, 107 Minivan 25 Pickup box deletion 72 Pinion gear 42–43 N Planetary gears (transmissions) 87 N/V, engine rpm per mph 82 Platform architecture 22–24 calculation examples 82–83, 85, 94, 107 table: tire-axle ratio combinations 128 Porsche boxer engine 23 National Highway Traffic Safety Admin- istration (NHTSA) Power brakes 117 SUV definition 20–21 Power curves 75–78 Naturally-aspirated engine 108 Power demand calulations Net horsepower 75 air resistance 91–92, 94, 130 grade resistance percent 92, 94, 130 Net torque 75 rolling resistance (GVW) 91, 94, 129 O Power loss altitude and heat 108 Occupant weights driveline friction 89–90, 96 location and distribution 54–55, 56, 58–59, 60–61 Power reserve weight per person 31 and gradeability 92, 94–95, 107 Oldsmobile Power steering 116 longitudinal fwd 25 Power take-off (PTO) 119, 135 Toronado 25 Powertrain 22, 24, 26, 78–79, 88–89 On/off road (all-terrain) tires 47 Overall gear reduction (overall ratio) 81

TMI Precision Truck Training Light Truck Essentials

A 15 Page 142 Index

Sport-utility vehicle (SUV) 20–21 R body-on-frame 25–26 Radial ply tires 46–47, 48, 91 crossover 22, 25, 36, 41, 44 Radiators definition by NHTSA 20–21 design and specifications 113–114 Spring ratings expansion (surge) tanks 113 deflection rate 44–45 Ram, early Dodge SUV 20 ground rating 45 Rear-wheel drive (rwd) 21–22, 24–25 pad rating 44–45 Rear axles 41–42 Spring types full-floating 42 air bag 44 load rating 42 coil 44 Salisbury 41 leaf 44 semi-floating 42 torsion bar 44 torque rating 43 Stabilizer (anti-roll) bars 46 Resisting bending moment (RBM) 38–39 Startability (launch performance) 79, 88 Ring gear 42–43 Starter motor 111 Rocker arms (OHV engines) 28 Steering systems Rolling radius (tire) 135 power 116 rack-and-pinion 115–116 Rolling resistance 96 ratio 116 power demand 91, 92, 94, 129 recirculating ball 115 radial vs bias ply tires 47, 91 Subaru boxer engine 23–24 S longitudinal fwd 25 SAE (Society of Automotive Engineers) Supercharging 109 6-bolt PTO port 119 engine performance ratings 75 Suspension systems 39 Safety systems antilock brake systems (ABS) 118 T electronic traction control 118 Tare weight 30, 31, 63, 64, 67, 70 vehicle stability control (VSC) 118–119 Temperature control (cooling) 113–115 Salisbury (3-piece) axle 41 Three-Way Test 54, 59, 101–102 Section modulus 37, 38, 39, 40, 135 Tire-axle ratio combinations 128 Section width (tires) 48–51 table of engine speeds 128 Semi-floating axle 42 Tire and Rim Association 51 Shift pattern chart 83, 84 Tire inflation pressure Shock absorbers 46 and load ratings 49, 50, 52 and ply rating 49 Short & Long arm IFS 40 Tires Side valve engine (L-head) 27 bias-ply 47 Spark-ignitied engine 26 load range 48–50, 134 Spiral-bevel axle gearing 42–43 load rating at max. inflation 50, 127 LT-metric 48, 49, 50 P-metric 48 ply rating 49, 135 radial-ply 47

Light Truck Essentials Precision Truck Training TMI

A 15 Index Page 143

rolling radius 135 Transverse engine 24–25 section width 48–51 front-wheel drive 24–25 size designations 48 Tread/track width 32–33 sizes and dimensions 48 wheel and tire sizing 50–51 Tread design 47 Tire tread designs Truck weights and ratings all-season 47 gross vehicle weight (GVW) 30, 31, 32 all-terrain (on/off road) 47 gross vehicle weight rating (GVWR) 30, highway commercial 47 31, 32, 33 Tongue weight (trailer) 100–101, 135 Turbocharging 108, 135 hitch load 101–103 and intercooling 109 percent of trailer weight 100–101, 103 performance advantage 108 Ton rating 33–34 Turning circle curb-to-curb 115 Top dead center (TDC) 27 wall-to-wall 115 Torque (lb-ft) Two-stage leaf springs 45 description and explanation 74–75 power relationship 76–77 Two-wheel drive 21 torque curve graph 76 front drive (fwd 4x2) 21–22 rear drive (rwd 4x2) 21–22 Torque converter 79, 86, 87, 88 SUV definition 21 Torsion bar springs 44 Towing loads and ratings 104 U trailer weight (GTW) 104–105 Unibody, unitized body-frame 25–26, 36 truck-trailer rating (GCWR) 104–105 Unsprung weight 45 truck-trailer weight (GCW) 104–105 and spring ratings 45 Traction control electronic 43 V limited-slip differential 43, 99 Vacuum brake booster 117 Trailer hitches Vacuum pump bumper (dead weight) 101–102 and diesel engine 110 classes 103 fifth-wheel 104–106 Valves, inlet and exhaust 26–27 kingpin load 105, 106 Van weight distributing (equalizer) 102–103 cargo 25 Transfer case passenger 118 with all-wheel drive 22 Vee-type engine 23, 27 with four-wheel drive 22, 98 Vehicle (electronic) stability control Transmission (VSC) 118–119 automatic 79, 86–87, 88 Vehicle (road) speed close ratio 132 and axle ratio 79–80, 85, 95 gear ratio 79–80, 88, 133 and N/V calculation 82–83, 85, 94, 107 manual 79, 87–88 and transmission gears 83–84 overdrive 81, 85 road speed by geared steps 79–81 Vehicle architecture 22–23 shift pattern chart 83–84 Volkswagen synchromesh 135 boxer engine 23

TMI Precision Truck Training Light Truck Essentials

A 15 Page 144 Index

Voltage 112 alternator vs. battery 112–113 Y batteries in parallel 112 Yaw and stability control 118–119 batteries in series 112 Yield strength 37, 38 W Z Water level loading 64, 67 ZF transmission 79, 89 weight distribution 64 gear ratios 79–80, 88 Watt, electrical power performance examples 93–95, 106–107 and current, voltage 112 Watt, James horsepower defined 77 Weight distributing (equalizer) hitches 102 calculation example 103 Weight distribution bodies 64, 67, 70 cargo weight 56–59, 62, 64, 67, 70 components 56, 67 defined 55, 136 occupants 56, 58–59, 60–61, 67 Weight ratings truck (GVWR) 30, 33 truck and trailer (GCWR) 100, 104–105 Wheel spin 43, 99, 118 Wide-open throttle (WOT) 75 torque rating 75 Work (ft-lbs) 74–75

Light Truck Essentials Precision Truck Training TMI

A 15